76 S. H. SCUDDER ON PALAEOZOIC COCKROACHES. 



long and 15 mm. broad, 3 and is therefore the largest, or one of the largest, of the species of 

 this genus; the breadth is to the length as 1 : 2.67; with a lens the entire surface is seen 

 to be covered with a delicate network of cross veins, connecting the veins by exact trans- 

 verse lines. 



The two species to which this insect is the most nearly allied are those between which it 

 is here placed. From both it is at once distinguishable by its far greater size; from Etobl. 

 carbonaria it differs in the less extent of the scapular area, the fewer number of veins in 

 the same area, and its earlier division. From Etobl. russoma it is separated by its nar- 

 rower and longer mediastinal area, and the less profuse branching of the scapular and 

 externomedian veins. 



Germar described the species from a single specimen and its reverse, found at Wettin, 

 German}'. According to Mahr, the species has been repeatedly found at Manebach, near 

 Iliuenau. German_y. Upper carboniferous. 



Acridites carbonaria, considered by some authors as the hind wing of this insect, is 

 rather to be looked upon as neuropterous. Blatta didyma Germ.-Ber., is an amber insect, 

 which does not belong to the Palaeoblattariae. 



Etoblattina russoma. PL 2, fig. 6. 



■Blattina russoma Gold., Neues Jahrb. f. Mineral., 186!), 159, taf. 3, figs. 2 a , 2\ 2 B ; — lb., 



Faun, saraep. loss., ii, 20. 



The front wing is tolerably broad, the costal margin very regularly and rather strongly 

 convex, the inner margin nearly straight to the tapering, well-rounded tip. The veins, 

 originate far above the middle of the wing, and have a slight upward curve for a short 

 distance. The mediastinal vein runs subparallel to the costal border, which it approaches 

 apically in a very gradual manner, and terminates shortly before the end of the middle 

 third of the wing; the area is less than one-fourth the breadth of the wing, and is filled with 

 seven or eight simple or forked, straight, oblique branches. The scapular vein has a broadly 

 but rather strongly sinuous course, running parallel to the costal margin in the basal two- 

 thirds of the wing, and beyond that curving toward the margin, terminating just before 

 the tip ; it begins to divide in the middle of the basal half of the wing, and emits about 

 five branches, which become less and less compound apically, but terminate on the 

 margin in about a dozen closely crowded branches; this area occupies more than one-third 

 the breadth of the middle of the wing. The externomedian vein is broadly and rather 

 strongly arcuate next the base, afterwards nearly straight, terminating at some distance 

 before the end of the inner border; it commences to divide at some distance before the 

 middle of the wing, but further out than the scapular vein, and bears a couple of com- 

 pound branches, which subdivide irregularly many times, and fill with numerous veins an 

 area larger than usual in this genus, occupying upon the margin not only the whole of the 

 apical border, but an equal extent of the extremity of the inner border. The interno- 

 median vein is parallel and close to the externomedian vein throughout its course beyond 

 the basal curve, and emits about half a dozen long, generally simple and nearly straight 

 branches, parallel to and rather distant from one another; so rapid is the narrowing of the 



1 Gerrnar give? the measurement as 30 mm. long and latter are also inaccurate, as the wing is not three times as 



lo mm. broad; but evidently by mistake, as it disagrees both long as broad. The figures we have taken are from measure- 



wiih the dimensions of his unenlarged figure and his Ger- ments of the smaller figure in the Wettin fossils, 

 man measurements (is Hues long by 6 lines broad); these 



